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Climate Hustle

Does Climate Change Really Matter?

Posted on 22 September 2010 by Kevin Judd

Guest podcast by Kevin Judd
(a transcript of a radio podcast)

Climate scientists are telling us that the earth's average temperature is going to rise 2 to 3 degrees over the next 50 to 100 years. But does it really matter that temperatures will rise this much?

You might think that this rise tempertures only means that winters will be a little milder and summers a little hotter, which does not sound like something to be bothered about. Unfortunately, it is not that simple. The effects you are most likely to experience is an increase in extreme weather. For example, an increase in extreme heat-waves in summer, and at other times an increased likelihood of heavy rain, hail, and high winds, that lead to flooding and wind damage. In higher latitudes heavier snow falls are expected too, which might seem contradictory, but it is not.

So why does global warming cause an increase in storms? Big storms and extreme weather require a lot of energy to drive them. You might know that a pot will simmer on the stove for long time, but turn up the heat just a little, and it soon boils over. The same happens for big storms on earth. The additional heat from global warming means that the weather will more often boil-over into very big storms.

We are already seeing this happen. Insurance companies, who keep careful records of damaging storms, have seen the frequency of big storms triple in the last 30 years. Big storms that used to occur only once every one hundred years are now ocurring about every 30 years. Similarly, heat-waves are more common and severe, which, of course, means more wild fires.

Scientists cannot attribute to climate change any one extreme weather event, like say the recent hail-storm in Perth, or the flooding in Pakistan, but the trend to increasingly extreme weather can be directly attributed to global warming.

Anyone who tells you that you and future generations are not going to be effected by the consequences of climate change, either does not understand how weather and climate works, or is being deliberately misleading.

In my next segment I will consider what we can all do to prevent the damaging effects of climate change.

NOTE: this post is also being "climatecast" by Kevin Judd on RTR-FM 92.1 around 11.30 AM WAST today. You can listen to a streaming broadcast of RTR-FM online via Please keep in mind that these podcasts are intended for a general audience and required to be less than 3 minutes.

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Comments 1 to 44:

  1. There is no upswing in extreme weather.
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  2. #1 cruzn246

    This is a science site. Please present compelling evidence when you make claims, so that we'll know why we should listen to you instead of, say, Thomas Karl, or the World Meteorological Association.
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  3. Is there a rss feed for the climatecast?
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    Response: RTR FM have a podcast page but not specifically for the fortnightly climate podcast. If people are interested, I could ask the UWA folk whether it would be possible to host their audio recordings on Skeptical Science.
  4. A suddenly appearing, prolonged 2-3 degrees rise of the ambient temperature in humans leads to a situation where the individual in question normally goes to a doctor.
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  5. cruzn246 - "Record High Temperatures Far Outpace Record Lows Across U.S.". And this is up to 2009 - 2010 is even warmer.
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  6. A good article. It is kind of curious to note, however, that for those of us who do not know RFR FM is an Australian station, the only clue that the text was written for Australians is the .au suffix in the URL (there are other cities named 'Perth' -- such as in Scotland).

    This is relevant, since there are other points in the article that are much clearer once you realize it was written for an Australian audience. The use of unadorned numbers for temperatures in degrees Celsius is a prominent example.

    Remember you WANT more Yanks reading your articles! But for us, 'degrees' measuring temperature as assumed Fahrenheit unless we are told otherwise. 2-3 degrees Fahrenheit really is small. But we can easily see 2-3 degrees Celsius as much more significant.

    I suggest the site deal with this problem by the use of the common convention of putting explanatory text, text not in the original transcript (since this was broadcast over the radio) in square brackets. So, for example, "rise 2 to 3 degrees" becomes, "rise 2 to 3 degrees Celsius". Likewise, 'Perth" becomes, "Perth, Australia".
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  7. Perhaps the following question might be more pertinent, "Does the dog wag the tail or the tail wag the dog?" Suppose that both are possible. Then the next question might be, "Could they ever occur simultaneously, and if they did, what would be the consequences?" "Scientists" believe that tail wagging indicates a state of conflict. People believe that happy dogs wag their tail, but many "happy dogs" have bitten people. This leads to the possibility that the tail may be wagging these "happy dogs," which makes them mad, so they bite you. Since a dog can't both be happy and mad at the same time, it is impossible that the dog is wagging the tail and the tail is wagging the dog at the same time. So there you have it.

    But what if a 2-3 °C rise in global temperature were to cause some weird change in a dog's disposition, such that it can be both happy and mad at the same time? Now the dog can wag the tail and the tail can wag the dog at the same time. That has never before been seen in nature, so no one knows what the outcome will be. Think what would happen to the poor dog if simultaneous dog wagging tail and tail wagging dog were to cause a "Positive Feedback."

    Now I don't believe in God, so I tend to think that man was not created in His image and can therefore become extinct, just as easily as any other "animal." Unless man can devise a way to live happily ever after with giant clouds of methane burbling up from the ground and oceans, he ought to be taking more seriously prospects of the "Day of Judgement."
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  8. “Big storms and extreme weather require a lot of energy to drive them.”

    Nothing could be further from the truth. Great storms require a considerable variation in energy over a small area.

    The violent weather phenomena occur in the specified temperature range. Hence warming - only if in a strictly defined temperature range - will increase the number of extreme events. The same cooling.

    This explains the theory of fluid mechanics. On the surface hydrophobic water droplets combine (and simultaneously disconnect) rapidly only in the specified temperature range. The increase in temperature causes the droplets merge is declining, growing up (more "lazy") drops consisting of several smaller drops. They join fewer and much milder.
    Also, if we treat the global atmospheric circulation as a cybernetic system, we understand that with the increase of the energy supply to such an system, he will be able to run additional feedbacks stabilizing system - number of extreme events as a result of warming MUST be reduced.
    Polish scientists (Natural Disasters, 2008.) write: "In the years 1701-1850, ie during the period when the Earth was in the so-called Little Ice Age in the Caribbean basin hurricanes were almost three times higher than in the second half of last century, and from 1851 to 1950 - twice as frequent. [!!!] Total number of tropical cyclones on Earth in the twentieth century, was twice smaller than in the nineteenth century [!!!]"
    In periods other former cooling (8-8,3; 5,1-5,7, 4.5 ≈ 2.1, and 2-1,6 thousand years ago) has always followed a significant increase in strength of ENSO - tropical cyclones ...
    In the United States during the beginning of Dalton minimum in 1780, the largest ever recorded in the so-called. "Great Hurricane" (much stronger than Hurricane Katrina) killed at least 22,000 people ...

    Currently, when the estuaries are much more densely populated ...

    Rising temperatures have already by 1.5 ° C will reduce the frequency of high-pressure system (anticyclones), the extension of the troposphere. Compared with the current temperatures, will reduce pressure gradient in the atmosphere, also lose their importance as barriers to the mountains.
    Beautifully seen an example of the Sahara. In the summer there are only shallow low-pressure systems, but only in winter powerful, stationary anticyclones (indeed, as in Siberia).
    Phenomena in the atmosphere does not occur linearly. Currently, Hadley cell expands. As a result of warming of 3-4 ° C, as always, extend, however, (on N and S) Ferrell cell. Hadley cell may even disappear - like cell zone separating the two areas of high pressure (the same way as - described above - in the summer in the Sahara).

    Heat waves in the NH (2003, 2006, 2010) are associated more with violent beginnings of La Nina - cooling of the oceans, fewer algal NPP - cloudiness (CLAW hypothesis).

    Global warming and United States landfalling hurricanes, Wang and Lee, 2008.:
    “Warmings over the tropical oceans compete with one another, with the tropical Pacific and Indian Oceans increasing wind shear and the tropical North Atlantic decreasing wind shear. Warmings in the tropical Pacific and Indian Oceans win the competition and produce increased wind shear which reduces US landfalling hurricanes.”
    The authors also say:
    “This paper uses observational data to demonstrate that the attribution of the recent increase in Atlantic hurricane activity to global warming is premature and that global warming may decrease the likelihood of hurricanes making landfall in the United States.”
    “The accumulated cyclone energy index, which has been used to measure tropical cyclone activity, is also observed to have a downward trend for global hurricanes over the past two decades when consistent satellite imagery has been available.”

    May vary regionally (IV IPCC report and „... the North Atlantic to warm more slowly than other oceans ...” - weakening of the AMOC - cooling of the North Atlantic) and the gradient of "vertical wind shear" may rise.

    However, declining globally (with warming) gradient of "vertical wind shear" decides to lower the intensity and frequency of all storms, not just the big.
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  9. The effects you are most likely to experience is an increase in extreme weather.
    Actually, might it not be more likely that the effects most readers (who will be more likely to come from relatively rich developed countries with more moderate climates) will be the knock on effects of extreme weather elsewhere, experienced as economic turbulence and the political effects of food insecurity. But hard to know exactly what is going to hit a given person personally first. Some may experience extreme weather directly, but I suspect that many more will face knock on consequences of declining food production. That is, climate change will probably affect many people in ways that they don't think of as due to climate change, but it will be one of the significant background causes.

    @Roger A. Wehage
    Now I don't believe in God, so I tend to think that man was not created in His image and can therefore become extinct
    I do believe in God and tend to think that humanity was created in God's image, but I also think that we can become extinct. There is no divine promise of personal or civilisational protection.
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  10. Re: cruzn246 (1)
    "There is no upswing in extreme weather."
    Your Jedi mind tricks won't work on us here.

    The Yooper
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  11. There's a minor grammatical error in the second to the last paragraph. I believe that would be "affected" not "effected."
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  12. I agree with Mr. Judd’s argument. As Matt J. (comment 6) pointed out, 2-3 degrees Celsius is equivalent to 4-6 degrees Fahrenheit. An increase in several degrees might seem minute at first, but one needs to consider the scale upon which we are viewing these changes. Consider the human body for example. Our body’s hold a general temperature of around 98.6 degrees Fahrenheit; with a less than a two degree increase in our body’s core temperature we are classified as having a fever, entering a state of “sickness.” Now I know our bodies are different than the entire world; or, are they really that much different? The nature of the planet we live in is in no way less intricate than the incredible complexity of our bodies; both exist in a delicate balance. Countless systems work together in harmony under an ideal set of conditions. If the conditions in which these systems operate are altered even slightly, the consequences can be exponential. If you have a fever and catch a cold, are you able to operate at your normal day-to-day level? Now consider Earth “catching a cold,” the symptoms of our planet getting sick can be devastating not only now, but for future generations to come.
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  13. Kevin Judd:
    “Big storms and extreme weather require a lot of energy to drive them.”

    Arkadiusz Semczyszak response
    "Nothing could be further from the truth. Great storms require a considerable variation in energy over a small area."

    The Ville:
    Tell us something we don't know Arkadiusz.
    Since Kevin didn't actually define what a big storm was, I think you are making an assumption and then automatically correcting something without knowing what Kevin was referring to.
    If you weren't here to be deliberately negative, you would have asked for a clearer definition of what a big storm was and then made a comment on that.

    Arkadiusz Semczyszak:
    "...we understand that with the increase of the energy supply to such an system...number of extreme events as a result of warming MUST be reduced."

    The Ville:
    By your own definition you are incorrect. You earlier stated "Great storms require a considerable variation in energy over a small area.", not increased or decreased energy.

    Arkadiusz Semczyszak:
    "Polish scientists (Natural Disasters, 2008.) write: "In the years 1701-1850, ie during the period when the Earth was in the so-called Little Ice Age in the Caribbean basin hurricanes were almost three times higher than in the second half of last century."

    The Ville:
    Sorry, 'Polish scientists' were cherry picking or wildly wrong.
    See Ricardo García-Herreras work on Spanish records of hurricanes in that area and era. Given that the Polish were no where to be seen as far as Atlantic exploration is concerned, I think Spanish records are probably more accurate. Specifically between 1576 and 1601 there was a huge peak, they then dipped until 1760, then started peaking again. eg. during a large chunk of the 'LIA' there were both larger numbers and fewer.
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  14. “By your own definition you are incorrect.”

    No. At the hydrophobic surface sufficiently heated, drops generally do not combine - do not join because they do not ... The liquid forms a uniform layer. Violent phenomena virtually disappear. That's why (among other things + no Panamanian isthmus) in the Oligocene tree ferns (with extremely fragile stems) grew almost from the equator - practically to the North Pole - around - so defined area - and in addition, the same species.
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  15. I find this post disappointing for its lack of data to support the premise that warming will drive more extreme weather events. Where are the peer reviewed papers, statistically significant trends, and large (not cherry-picked) data sets?

    In the absence of any supporting data, articles like this discredit the generally solid scientific story behind global warming. Furthermore, it provides fodder for the distractions that deniers tend to latch onto.

    I'm not saying it is or isn't true, but the lack of data or references is a red flag. In the absence of any data, I could argue that greater warming in the polar regions will result in smaller temperature gradients in general, and therefore less extreme weather. (Don't anyone get worked up - it is just to make a point about the need for evidence.)

    Sure, the post is a podcast, but the bar must be set higher for inclusion on this site.
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    Response: It was for this reason that Kevin asked me to specifically mention this was a transcript of a very short message for a broad audience. Kevin is probably the only climate scientist I know whose public communications are accused of being too simple (and I'm not sure he's a big fan of that fact). Other posts on extreme weather such as the page about record snowfall and extreme precipitation events feature many peer-reviewed references. However, currently there is a diverse range of styles on offer at Skeptical Science - both basic, light pieces and detailed, technical articles. It is all part of a plan :-)
  16. Arkadiusz you haven't responded to a remark I have made. It doesn't even relate to your own previous comment. Instead you have gone off in some unrelated tangent.
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  17. The carbon dioxide emissions from burning fossil fuels have melted the Arctic sea ice to its lowest volume since before the rise of human civilisation, dangerously upsetting the energy balance of the entire planet, climate scientists are reporting.

    "The Arctic sea ice has reached its four lowest summer extents (area covered) in the last four years," said Mark Serreze, director of the National Snow and Ice Data Center in the U.S. city of Boulder, Colorado.

    The volume - extent and thickness - of ice left in the Arctic likely reached the lowest ever level this month, Serreze told IPS.

    "I stand by my previous statements that the Arctic summer sea ice cover is in a death spiral. It's not going to recover," he said.

    Source: “Arctic Ice in Death Spiral,” IPS, Sep 20, 2010

    I encourage everyone perusing this comment thread to read this article in its entirety.

    The predictied changes to the Arctic climate system that is already built into the system will have profound effects on the global climate system.
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  18. @Arkadiusz

    "Heat waves in the NH (2003, 2006, 2010) are associated more with violent beginnings of La Nina - cooling of the oceans, fewer algal NPP - cloudiness (CLAW hypothesis). "

    Only 2010 was begining of "violent" La Nina as i think.
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  19. Thanks, John, for the reply regarding data supporting extreme weather. The link and references therein were helpful.

    But still, we must be careful about attributing too many weather events to global warming, without solid evidence. In my view it is one of the weakest aspects of the "alarmist" positions.
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  20. @ianw01: that's why it's always safer to say that an increase in extreme weather events is "consistent" with AGW theory.
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  21. ianw01 at 23:42 PM, all weather events, extreme or otherwise, are driven by the same combination of a heat differentials and moisture, and they all unfold the same way.

    As the water vapour picked up rises, it gradually releases heat, condensing out forming different cloud types in sequence until finally the air becomes dry above where cirrus clouds are the last to form.

    The albedo effect dominates the low altitude clouds, so they then provide a nett cooling effect to the Earth's climate.
    However uncertainty remains about the high level cirrus clouds, which alone cover about 35% of the earths surface, but as this passage from a CLOUDSAT overview would indicate, linking extreme weather events with climate change is treading on uncertain ground as you noted.

    "Because clouds have such a large impact on Earth’s radiation budget, even small changes in cloud abundance or distribution could alter the climate more than the anticipated changes in greenhouse gases, anthropogenic aerosols, or other factors associated with global change. Changes in climate that are caused by clouds may in turn give rise to changes in clouds due to climate: a cloud-climate feedback. These feedbacks may be positive (reinforcing the changes) or negative (tending to reduce the net change), depending on the processes involved. These considerations lead scientists to believe that the main uncertainties in climate model simulations are due to the difficulties in adequately representing clouds and their radiative properties."
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  22. Shorter johnd: More convection will manifest itself invisibly.

    Or something like that.
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  23. doug_bostrom at 10:04 AM, re "or something like that"
    That drives direct to the quintessence of the dilemma as it stands.
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  24. #15:"lack of data to support the premise that warming will drive more extreme weather events."

    For context, here is an interesting summary of the changing pattern of observed climate extremes during the 2nd half of the 20th century (from 2002):

    Observed coherent changes in climatic extremes during the second half of the twentieth century Frich et al. 2002

    Coherent spatial patterns of statistically significant changes emerge, particularly an increase in warm summer nights, a decrease in the number of frost days and a decrease in intra-annual extreme temperature range. All but one of the temperature based indicators show a significant change. Indicators based on daily precipitation data show more mixed patterns of change but significant increases have been seen in the extreme amount derived from wet spells and number of heavy rainfall events. We can conclude that a significant proportion of the global land area was increasingly affected by a significant change in climatic extremes during the second half of the 20th century. ...

    ... for the global land areas examined, on average during the second half of the 20th century, the world has become both warmer and wetter. ... These observed changes in climatic extremes are in keeping with expected changes under enhanced greenhouse conditions.
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  25. Further to muoncounter's remarks, it's odd that some skeptics are recently touting increased convection as an easy and hopefully transparent means of somehow avoiding energy gain on the planet.

    Strange events such as the 9.6" of rain in 36 hours (normally 4.5" for the month) causing a historically novel flood in Bella Coola, BC last weekend may offer hints that we should not expect intensified convection to be benign, let alone a magic pathway to the stars for energy.

    On a grander scale than charming but tiny Bella Coola, try HowBigReally to see Pakistan's flooding this year, compared to California, USA. Tip of the hat to Skeptical Science's host country, here's Australia compared to Pakistan's rising damp.
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  26. #25: "some skeptics are recently touting increased convection"
    Seriously? Are they running out of arguments?

    From MIT's Center for Global Change Science: But convection has two competing effects: increased convection forces increased subsidence in the environment of clouds, which is a strong drying effect; but increased convection also increases the rate at which water vapor from near the Earth's surface is transported to higher altitudes. However the bulk of this water vapor condenses as it rises and falls out as precipitation leaving open how much is actually available to moisturize the atmosphere.

    Doesn't that suggest that increased convection -> more precipitation, just like the events you describe?
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  27. Yes, muoncounter, more precipitation seems to be the inevitable outcome but the assumption is apparently that it will have no deleterious effect on human culture, regardless of the exact manner of distribution.

    Meanwhile, there will never be a shortage of arguments. We are nothing if not ceaselessly inventive.
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  28. #27: "no deleterious effect on human culture, regardless of the exact manner of distribution."
    Curiouser and curiouser. I thought there was ample precedent for problems caused by an excess of rain.
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  29. Muoncounter, no, absolutely there's no way to have too much water. Witness Stanislav Lem's character Ijon Tichy:

    ...Tichy has to escape from a planet whose government has legislated that all of its inhabitants shall henceforth breathe underwater. The citizens sing patriotic anthems about fish and humidity, and learn that in a future paradise all shall become "gwats" and "sunkers," idealized water-breathing forms. Debates rage over whether gurgling is allowed.

    Perhaps pro-fossil fuel lobbyists are bureaucrat emissaries from another planet, tricking libertarians here into joining their submarine totalitarian aquatopia?
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  30. How could I have missed that? And to think, all those years studying sophistry at dear old More Science High, wasted.
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  31. A little more on LA:

    The mercury hit a blistering 113°F (45.0°C) at 12:15 pm PDT yesterday in downtown Los Angeles, making it the hottest day in Los Angeles history. It may have gotten hotter, but the thermometer broke shortly after the record high was set. The previous record in Los Angeles was 112°F set on June 26, 1990; records go back to 1877. Nearby Long Beach tied its hottest all-time temperature yesterday, with a scorching 111°F. And Christopher C. Burt, our new featured blogger on weather records, pointed out to me that a station in the foothills at 1260' elevation near Beverly Hills owned by the Los Angeles Fire Department hit 119°F yesterday--the hottest temperature ever measured in the Los Angeles area, tying the 119°F reading from Woodland Hills on July 22, 2006.

    Jeff Masters

    "The thermometer broke"; if only it were the old movie gimmick, featuring an exploding liquid thermometer.
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  32. How would 2010 be if we had the same El nino and solar pattern as 1998?

    1998-2004 had a solar max that had 140-150 sunspots to 20-30 sun spots and predictions of 50-60 for the peak within the next few years...Take off .1c?

    Now onto the El nino-1998 based on this map had 2.8c at 3.4, but 1.8c during January 2010. That is 1c difference.

    This is more support for a 2.8c over 3.4 in 1998.

    This is only one part of the world, but a huge part of the world and would very likely make sst's number one by a large margin if it was occurring now. So all together you bet we would be warmer and no one would be able to cover it up either. I will guess .2-.3c over 98 for such a year. Do you think that is close?
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  33. The present Tory UK Foreign Secretary delivers reasons why climate change matters, from a foreign policy perspective:

    I will first argue that an effective response to climate change underpins our security and prosperity. Second, our response should be to strive for a binding global deal, whatever the setbacks. And third, I will set out why effective deployment of foreign policy assets is crucial to mobilising the political will needed if we are to shape an effective response.

    To learn more about what a usefully functional conservative grounded in reality sounds like when confronted with facts, click the link.
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  34. Another way of asking, "does climate change really matter?"

    Just another coincidence in the weather, surely.

    Graph from this article, which makes today's coverage of the Powell-Mead system in the NY Times look optimistic.
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  35. This WMO summary of the summer of 2010 makes delightful reading.

    Climate extremes have always existed, but all the events cited above compare with, or exceed in intensity, duration or geographical extent, the previous largest historical events. ...

    The occurrence of all these events at almost the same time raises questions about their possible linkages to the predicted increase in intensity and frequency of extreme events, for example, as stipulated in the IPCC Fourth Assessment Report published in 2007. The Report stated that “…the type, frequency and intensity of extreme events are expected to change as Earth’s climate changes, and these changes could occur even with relatively small mean climate changes.

    They go on to mention Stott, Stone and Allen 2004 Human contribution to the European heatwave of 2003: it is very likely (confidence level >90%) that human influence has at least doubled the risk of a heatwave

    Does it really matter?
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  36. Sorry to break into the vitriol with a real question...

    But I do not understand.

    The implication of the main article is that the 2-3C temperature rise is not the main problem. As the article states, a small temperature change is not something to be bothered about.

    Instead, is the real issue with the increase in wild weather?

    Is the temperature rise simply a proxy for representing a bunch of other climatic events?

    I have to confess, I have never really understood why a small change in temperature could have such a big effect on civilizations. If, however, temperature was a proxy for storm energy, then this would be a different understanding.

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  37. One of way of thinking of this, mfripp, is that if my house should burn down, I will not be able to comfort myself with the thought that my neighborhood did not noticeably warm up.

    Some of the problem is indeed with "wild weather"; presently there's an extra accumulation of something like 4000 petawatt hours/year of energy on Earth happening and unless it's really smoothly distributed the effects are expected to be noticeable in visibly dramatic and kinetic ways. That translates into things like this:

    For example, the "hundred year flood" was once something that you had better be aware of, but it was not very likely soon and you could get reasonably priced insurance. But the probability distribution function does not need to shift very far for the 100-year event to be occurring several times a century, along with a good chance of at least one 500-year event.

    -- NASA-GISS: 2010 — How Warm Was This Summer?

    Speaking of weather, Kevin Trenberth says:

    I find it systematically tends to get underplayed and it often gets underplayed by my fellow scientists. Because one of the opening statements, which I’m sure you’ve probably heard is “Well you can’t attribute a single event to climate change.” But there is a systematic influence on all of these weather events now-a-days because of the fact that there is this extra water vapor lurking around in the atmosphere than there used to be say 30 years ago. It’s about a 4% extra amount, it invigorates the storms, it provides plenty of moisture for these storms and it’s unfortunate that the public is not associating these with the fact that this is one manifestation of climate change. And the prospects are that these kinds of things will only get bigger and worse in the future.

    -- NCAR’s Trenberth on the link between global warming and extreme deluges

    The "vitriol" about convection is reflective of frustration with the idea that so much energy can be wished away.
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  38. 2-3 C sounds like a little temperature change ... but that's misleading, because a small temperature change averaged over the entire globe is actually a huge change in the climate.

    For comparison, global temperatures at the last glacial maximum were about 8 C lower. So that 2-3 C is about a quarter to a third of the change between my home being in a comfortable temperate forest and my home being buried under 2000+ meters of ice.
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  39. Searching for a new rhetorical device, Doug and I simultaneously come up with the same idea:

    Doug: One of way of thinking of this, mfripp, is that if my house should burn down ...

    Me: ... my home being buried under 2000+ meters of ice.

    Some say the world will end in fire,
    Some say in ice.
    From what I've tasted of desire
    I hold with those who favor fire.
    But if it had to perish twice,
    I think I know enough of hate
    To say that for destruction ice
    Is also great
    And would suffice.

    (Robert Frost)

    What's next ... muoncounter's house destroyed by a volcano?
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  40. Ned, I recognize that the difference between the last glacial maximum and now was 8C. Nonetheless, I do not understand it. The science is proven, but it does not mean that I understand the science.

    Do you have a Climate Science 101 answer or reference for why small changes in average temperature have such a large effect on the climate?
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  41. Re: mfripp (40)
    "Do you have a Climate Science 101 answer or reference for why small changes in average temperature have such a large effect on the climate?"
    You essentially are referring to the sensitivity of the climate to forcings, both negative and positive, the net effects of which can and have changed over time.

    It is the recent admixture of human-derived fossil-fuel CO2 concentration emissions (which depart from the paleo record of the balance between the forcings which has driven temperature and climate changes in the past) which now drive a rate of warming change (read: euphemism for the "Hockey Stick") for which there exists no comparative example in the paleo record.

    I plugged "climate sensitivity" into the search box available at the upper left of every Skeptical Science page and got this.

    Of the resulting Skeptical Science posts available, this is the one probably most pertinent.

    If you would rather a source with a summary outside that of Skeptical Science, I plugged your quote into Google and found this site, which seems to offer a fair-balanced, relatively non-technical, summary as well.

    If you wish to further deepen your knowledge and understanding of Climate Science, I would refer you to Real Climate's Start Here page. Pay particular attention to Spencer Weart's The Discovery of Global Warming article; another virtually required viewing source is Richard Alley's talk on CO2: The Biggest Control Knob.

    Hope this helps,

    The Yooper
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  42. Re: My comment at 41 above

    Upon re-read, my 2nd paragraph seems a bit obtuse. Sorry for that. Here's a re-try for clarity:

    Humans have whacked the carbon cycle with a mountain of carbon. This bolus, or "slug", has upset the natural balance between forcings and has driven the current upward "spike" in temperatures. Temperatures will continue to rise, due to the physics of radiative gases, until a new equilibrium is reached.

    Note: as long as the CO2 concentration continues to rise, achievement of temperature equilibrium will be delayed and temps will continue to rise. Thus, any further continued release of fossil fuel derived CO2 makes things worse.

    Even if CO2 emissions are immediately reduced to zero and maintained at zero for 30 years, temperatures would continue to rise due to the immense thermal inertia of the oceans, where 93% of the warming of the system has currently gone. This warming of the oceans is driving a reorganization of the climate system, which will continue to change as long as the CO2 emissions and temperatures rise.

    It is that lag in response wherein lies the danger. By the time incontrovertible evidence (to the layman) exists, it will be too late to avoid or even mitigate the worst of the changes still in the pipeline. And that only takes into account the short-term forcings. Longer-term responses (century to millennial timescales) include forcings which will effectively double any warming we will see in our lifetimes.

    The warming already in the pipeline may be sufficient to obliterate our ability to feed the world's current population. Thus, for some of those alive today, it may already be too late. Hence the calls for action and the existence of this and similar websites.

    That sounds a bit more clear, I think.

    The Yooper
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  43. #40: "Do you have a Climate Science 101 answer or reference for why small changes in average temperature have such a large effect on the climate? "

    I thought Ned made that point in #38: "a small temperature change averaged over the entire globe is actually a huge change in the climate", ie, the heat energy equivalent of 2-3C throughout the volume of the atmosphere is quite large. We're already seeing big-time changes in a mere 1C.

    As far as #39 "muoncounter's house destroyed by a volcano?" is concerned, I'm riding happily on the margin between stable craton and gently subsiding miogeosyncline. I'm far more likely to go due to a late-season hurricane.
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  44. Daniel,
    Thank you for the references. I especially like Richard Alley's talk and Spencer Weart's article. I'm going to need some time to digest these articles.
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